Karl prinzler



UNITED STATES PATENT OFFICE KARL PRINZLER, OF GOTI-IA, GERMANY.

PRODUCTION OF MOLDING AND CORE SAND FOR CASTING.

SPECIFICATION forming part of Letters Patent No. 553,688, dated January 28, 1896.

Application filed August 2, 1395. Serial No. 557,986. (No specimens.)

To all whom it may concern;

Be it known that I, KARL PRINZLER, foundry-foreman, a subject of the Emperor of Germany, and a resident of Gotha, in the Grand Duchy of Saxe-Ooburg-Gotha, Germany, have invented new and useful Improvements in the Production of Molding and Core Sand for Casting, of which the following is a specification.

Molding andcore sand is at present prepared for casting purposes by taking unused sand of one kind or a mixture of several kinds, either burning the same or mixing it with sand which has already been used for molds, and finally moistening the mass with water and thoroughly raking over or screenin g. For wet casting coal-dust is added, and, according tothe nature of the several kinds of sand, they are either ground fine or left in their original condition. All kinds of sand are not suitable for molding, and it is often necessary to procure the sand from considerable distances.

Even with molds and cores made of sand prepared as 'above cracks are produced on drying, which necessitates mending and reblacking of the molds and cores. Also, adhering particles of sand, which are often burned into the casting and damage the turn ing-tool, can generally be removed from the casting only with great difficulty, so that the cleaning of the castings takes much time and trouble. Lastly, in preparing the moldingsand, only a small proportion of the sand originally used can be re-employed, because this is rendered too poor and fine through the heating, and a large proportion thereof would weaken the mold and would not permit the escape of the gases produced in casting. It has been proposed to obviate these disadvantages by mixing with the sand tar, asphalt, or similar bodies. No doubt sand prepared with this admixture is more plastic than ordinary sand, and the molds and cores are hard and porous after the drying, but the employment of such sand is subject to other considerable defects which render its general use impracticable. Thus molds and cores prepared with tar-sand cannot be repaired if parts thereof are broken off or damaged, since the tar-sand does not take up water and consequently does not combine with repairingsand. Again, on using tar-sand for molds and cores in casting very unpleasant vapors that cannot be endured for any length of time are produced. Furthermore, the complete admixture of a large quantity of sand with tar is subject to great difliculties. A large storing-space is necessary and a storage of several days is required for the sand treated with a tar solution to become uniformly impregnated with the liquid. Lastly, the preparation of the tar-sand is very unpleasant, as the matter adheres to clothes, hands, and face, and its removal is difficult. For these several reasons the use of tar-sand in molding has gradually been given up.

The present invention has for its object the use for admixture with molding-sand of a more or less thin watery paste formed from the residue resulting from oil-manufacture and commonly called oil or press cake. For the purpose of my present invention I use rape or linseed cake, but the residue from other oleaginous vegetable matter may be used. By means of this admixture with the molding-sand all the advantages that were sought to be attained by the use of tar-sand are gained and at the same time all the defects attending the use of such material are avoided.

By the admixture of a watery paste of rape or linseed cake or like oleaginous residue with the molding-sand a plastic easily-worked sand is obtained, which can be mended like any other sand and which, in casting, produces absolutely no unpleasant gases. The molds and cores made of molding-sand with the addition of rape or linseed cake, or the like, are not liable to disintegrate at the surface during the castingthat is to say, no particles of sand become detached from the surface. The surfaces of molds and cores prepared of such sand are exceedingly clean and smooth, and the molds are also very porous, so that the gases evolved in the casting can pass away freely without causing the surfaces of the casting to become uneven, honeycombed or porous. On the contrary, the castings produced in molds made of a mixture of sand with rape or linseed cake, or the like, show a surface much smoother and more free from air bubbles or pores, and a fine uniform color, which last-named fact shows that the admixture of the rape or linseed cake, or the like, with the molding-sand, has a very advantageous influence on the casting. Furtherm ore, dried cores prepared from this sand are exceedingly friable after casting and can be removed from the castings with the greatest ease, and generally the cleansing of the castings can be effected better than with the tarsand, and with considerably greater facility than with ordinary molding-sand. The improved sand is equally applicable with advantage for molds and cores whether for dry or for wet casting.

The admixture of rape or linseed cake, or the like, with molding-sand is also of the greatest importance from the fact that not only the poorest sand of any description can be used as effectually as the usual sands best adapted for molding purposes, but that the burned-out sand which heretofore had to be removed from the foundry, because it was of no further use, can be used over and over again, with or without addition of a very small quantity of new sand of inferior quality. By this means not only the expense incurred in many foundries on account of having to obtain a suitable molding-sand from great distances is saved, but also in many cases the considerable expense caused by having to convey-away the useless and burned sand.

It is only necessary to provide new sand to make good for unavoidable waste, and in addition to provide for a very small quantity for regenerating the usedmolding-sand; but for this purpose the poorest sand can be used, as this, when mixed with the material described, can be worked as well as the best and most cohering molding-sand that has heretofore been used.

For preparing the sand with the admixture of rape or linseed cake, or the like, the following mode of procedure is employed: The rape or linseed cake, or the like, is comminuted or reduced to small fragments, and the meal thus produced is mixed with cold or, preferably, warm water in suitable receptacles to form a thin paste. This mixture is left for a suitable time in the receptacles with frequent or continuous stirring, and is then poured over the sand spread in a layer of suitable thickness, and previously mixed, and moistened with water, as usual. After the liquid paste has saturated the sand, this is shoveled up and then treated in the usual well-known manner.

The preparation of the molding-sand can also be eil'ected in the following manner, which is however not so advantageous: The molding-sand is mixed in the usual manner. The ground rape or linseed cake, or the like, is then added and incorporated therewith, and the whole is then moistened with water and further treated in the usual manner.

In conclusion, it is to be observed that when the molding-sand is to be used for wet casting it is also of advantage to mix pulverized coal with the sand mixture before the addition of the rape or linseed cake, (whether this be added as a paste or dry.)

If the room available permits, it is of advantage to prepare the sand in large quantities and to allow it to lie for some days, and when using it to remove the oldest sand from below, while fresh quantities of sand mixed with the rape or linseed cake, or the like, are always added at the top.

\Vhat I claim as new is-- 1. The herein described process for the production of molding and core sand consisting in forming a moist mixture of the sand with oleaginous vegetable presseake, such as rape or linseed cake.

2. The herein described process for the production of molding and core sand consisting in mixing the sand with a watery paste of oleaginous vegetable press-cake, such as rape or linseed cake.

3. Anew molding sand composed of a mixture of sand and comminuted oleaginous vegetable press-cake, substantially as described.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

KARL PRINZLER.

\Vitncsses:

A. STILLE IvEs, M. LoUIsE McDowELL. 

